A variety of air admittance valves and check valves have been developed for allowing air to enter a piping system or an enclosed environment under a negative or vacuum pressure, which is created when water flows down the drain, to prevent siphoning of traps or when a sump pump pumps water and air out of an enclosed sump pit. Attaching an air admittance valve or check valve allows ambient air to enter the enclosed environment to eliminate the negative pressure or vacuum in the enclosed system. Many of these valves are specifically designed for systems such as piping systems and sewer systems where it is difficult or impossible to install a local vent or air intake due to the difficulty of running pipes through an existing building. Typically, these air admittance or check valves only provide specific operating conditions such as, for example, the vacuum pressure in the amount of air required. Conventional air admittance and check valves available do not provide for instantaneous and higher volume of air demand, which is undesirable when existing air admittance components are installed on systems requiring the higher airflow demand because the higher airflow demand causes strain on the air admittance component and causes it to fail prematurely since the air admittance component was designed to function based on a natural gravity air flow vacuum or negative pressure constraint. Additionally, conventional air admittance components do not filter the air and therefore can allow for corrosive elements to pass through to the enclosed system, thus damaging the air admittance components and, potentially, the entire system.
In addition, an undesirable scenario is encountered when a negative pressure is generated in the piping system when flow is drained from the piping system. When such a negative pressure occurs, the water seals in the U-band or trap of the piping system will be siphoned out and can, therefore, no longer prevent sewer gas from entering the building. To address this issue, conventional air admittance and check valves have been designed to allow air to enter the piping system to prevent the negative pressure scenario. However, as explained above, conventional air admittance and check valves fail easily.
As such, there is currently no product available for a higher volume demand in a negative pressure scenario such as an enclosed pit with a pump requiring air to enter the system at the same rate at which water is pumped out. For example, a pump that pumps out 20 gallons of water per minute and would require a large demand of airflow to enter the system so that a vacuum is not formed in the enclosed environment resulting in stress on the pump and causing improper water discharge. In the case of a sump pump, the pump becomes air-locked and runs continuously, which causes the pump to overheat, burn out and/or fail resulting in flooding of the area and water damage to the building.
In many cases, a proper seal is required to provide a water and airtight seal after air has been allowed to enter the system and the pump disengages. Furthermore, if such an air admittance component does fail, the failure should occur in a closed/sealed position of the component to provide continued protection so that no fluid or gas can escape into the surrounding environment within the building or within a given height above the building's roof.
Although some check valves include a ball inside the valve to block or allow air flow through the valve, these conventional ball valves tend to fouled, which prevents the ball from achieving a perfect seal and blocking the air flow properly. A further drawback of conventional ball valves is the little to no rotation of the ball, resulting in wear of the ball from sealing at the same location.
A further drawback with conventional check valves is the lack of a failsafe in case a valve failure occurs. In other words, when conventional check valves fail, they cease to operate for their intended purpose. As such, two check valves are often installed in series, which is undesirable because this practice involves additional branch-offs and additional labor.
Therefore, the inventor has developed an improved valve assembly for use with an enclosed volume that needs to be vented.